Arrecife artificial

Concrete blocks, cubes and tube structures stand on a white sandy seabed in four clusters, and the dive is spent moving from one cluster to the next. Between the groups the sand is open, and garden eels, rays (electric rays among them) and angelsharks are seen there. On the structures there are octopus, nudibranchs, fireworms and morays, with schools of roncadores around the modules.

The boat leaves from Anfi del Mar, and the operator gives 4.5 nautical miles and 20-25 minutes to reach the reef.

Nothing on this seabed is natural: 84 modules of five designs, in concrete, reinforced concrete and fibre-cement, were set down in four groups on pale sand, and a diver can count them. The repeated shapes make the dive easy to read, a block, then a cube, then a tube, with bare sand between them where the garden eels stand. That sand is what photographers come for, since the light bounces off it onto the concrete. The reef was authorised as an experimental production reef across a zone of 150,000 square metres.

The Consejería de Agricultura y Pesca of the Canary Government applied for authorisation on 21 June 1989. The structures were finished on the seabed at 17-19 m in November 1991 under a provisional authorisation, with 30 November 1991 as the official laying date, and the final authorisation is a resolution of 16 December 1992 published in the official gazette on 20 January 1993.1 The authorisation prohibited all fishing in the reef's protected zone for three years from the laying date and required a three-year ecological and fishery monitoring plan.1

The reef is usually one half of a morning two-dive outing from Anfi del Mar, so the second dive of the trip is a separate briefing. Pack the camera for this one: pale sand under grey concrete is the draw, and the shapes sit in four groups, so a short lens covers a cluster at a time.